Machine readable Positive Sample Identification (PSI) must be part of any system intended to take full advantage of the capabilities of computers in the clinical laboratory. A computerized requisitioning program for all laboratory tests in all sections has been developed in this laboratory and the PSI is a part of a universal lab requisition form that is computer generated. This requisition card accompanies the specimen through all handling to the analytic station. The card contains all pertinent patient and specimen collection information. A laboratory data control station has been built with an integral card reader for specimen identification. This interface has a base unit that is independent of the specific instrument and computer. The station can receive data from the computer, log technologists' observations, and permits two-way communication. A specimen carrier holds the specimen and the ID portion of the universal laboratory requisition and stays with the specimen during centrifugation, incubation or other operations. The system is designed for on-line real-time data processing using a dedicated digital computer with major features for redundancy and graceful degradation. The technologist maintains responsibility for analyses. Provisions are included for the ready entry of technologist observations as to the state of the specimen.